He was in and out of jail for a series of petty crimes, although he has not been incarcerated for about a year and a half. He was not taking his training, or his career for that matter, seriously, although that has changed.

And Rios still has moments when he shows his immature side, such as in November when he was caught on video mocking the Parkinson's disease symptoms displayed by Manny Pacquiao's trainer, Freddie Roach.

But, all in all, Rios has grown up and fought his way to a shot at a world title. He will challenge titleholder Miguel Acosta of Venezuela on Saturday night (Showtime, 10 ET/PT) at The Palms Casino Resort in Las Vegas.

Rios (26-0-1, 18 KOs), nicknamed "Bam Bam," gained considerable attention with his third-round blowout of highly touted Jorge Teron in February 2010 and followed that victory with an upset win on HBO against Anthony Peterson. Rios dominated the fight, scored a knockdown in the fifth round and won when Peterson was disqualified for repeated low blows in the seventh round.

In his next fight, Rios took an assignment against Omri Lowther on short notice when Kelly Pavlik dropped off the Pacquiao-Antonio Margarito undercard in November and knocked him out in the fifth round at Cowboys Stadium.

"People that follow boxing know what a very terrific, competitive fight this is," Top Rank promoter Bob Arum said. "Brandon Rios has been fighting under the Top Rank banner for a number of years. In the last year and a half he has really come into his own with a tremendous victory over Anthony Peterson. He had a KO win [against Lowther] and now he's ready to fight for the WBA lightweight championship."

The win against Lowther set the stage for the title challenge against Acosta, but Dunkin said it would not have happened if Rios, 24, had not gotten serious about his career well before that fight.

"He changed. He became very dedicated to it, became dedicated to taking care of himself. He worked hard," Dunkin said. "He showed up to train every day and we got really excited about him. Who wouldn't? He was a national amateur champ several times over, had more than 200 amateur wins. You know he's got ability and you know he can fight. You just wanted to see him do it as a pro, and get better and learn and take care of himself."

Dunkin said the change came about 16 months ago.

"He met his wife and that was a big change in his life," Dunkin said. "He settled down and had a child. He wanted to do certain things in life. All of a sudden it became serious. It wasn't just about having fun and fighting. It was a serious career and a way to take care of his wife and child. It was just a whole new perspective. He grew up. All of a sudden, when he started really working, his skill level improved drastically. Brandon has been getting better and better and he will continue to get better Saturday night. [Trainer] Robert Garcia has done a great job with him. He's been really patient with him."

Challenging Acosta is the biggest opportunity of Rios' career and he plans to take advantage of it.

"I'm ready to become a world champion. And Saturday, I believe in my heart that I could become world champion, and I think I'm going to pull it off," said Rios, who grew up in Kansas but moved to Oxnard, Calif., about six years ago to train with Garcia. "I'm going to show the world that I'm ready for all the best lightweights out there. I'm ready for anybody.

"Everybody is going to see a new champion and it's going to be back in the United States. The belt is coming home, baby. I'm just a friendly guy, a guy that likes to enjoy what he does. I like the fans to enjoy watching what I do. Miguel Acosta is no joke. He is a strong fighter but he's just another guy. He's human, nothing I can't handle."

Acosta is used to being on enemy turf. He knocked out Urbano Antillon in the ninth round in his native Mexico to win an interim title in July 2009. And in May, Acosta (28-3-2, 22 KOs), whose record was recently amended by official record keeper Fight Fax, knocking off six losses mixed up with another fighter from his mark, went to the African nation of Namibia and stopped Paulus Moses in the sixth round to win his belt.

Now, he is excited to face Rios in Las Vegas, where Top Rank is based.

"To be here in Las Vegas, it's always been a dream of mine to fight here," Acosta said. "I know this is a great opportunity because many people will be seeing me for the first time. I'm coming to show people that I could be the best lightweight in the world. This is without a doubt the toughest challenge. But you know what? I'm ready for it and I will pass this challenge.

"My mentality is to fight the best lightweights in the world and this is the first big test, and there will be more to come. And I know I'll be coming back to make my second defense in Las Vegas.

"I think Rios is a strong fighter and he comes forward. I've been preparing for that. I plan to box him, take him into the late rounds and break him down. My sparring partners have been coming forward like him, so I can slip the punches -- not get hit, and do the damage. I'm going to defend my title and beat Brandon Rios on his home turf."

Acosta, 32, is riding a 19-fight winning streak since 2003, after losing three fights in a row, including by knockout in the second and third round. He has come a long way since then.

"Miguel Acosta is one of the hardest punching lightweights in the world today," Arum said. "He has a knockout win over Urbano Antillon. He has really good credentials. He went to Africa to fight an undefeated Moses, a terrific fighter, and he came away with another knockout victory, so he is the real goods."

"On paper, [this] does look like my toughest fight," Rios said. "All of my fights, I consider them tough. One punch can end your career. All of my fights, I take seriously. This one, I'm taking more seriously because of the fact that he is a champion and he didn't become a champion for no reason."

Garcia said Rios is ready.

"He's been waiting for this for a while," Garcia said. "He wants anybody at lightweight, the best in the lightweight division, that's why we picked Acosta. I truly believe Acosta is the best lightweight in the world, so we're in for a real fight. But Brandon has trained hard and his mind is set to become world champion and that's what's going to happen Saturday night."

Showtime will also air another notable lightweight match to open the split-site doubleheader as Mexicans Antonio DeMarco (24-2-1, 18 KOs) and Reyes Sanchez (20-3-1, 11 KOs) square off in Grand Island, Neb., in a title elimination bout. The winner becomes the mandatory challenger for a scheduled May 7 rematch between titleholder Humberto Soto and Antillon.

DeMarco, 24, has won his only fight since being stopped in the ninth round of a title bout by the late Edwin Valero in February 2010 in what was Valero's final bout before committing suicide. Reyes will be fighting in the United States for the first time.

Showtime will use two broadcast teams, one from each site. Steve Albert and Al Bernstein will call the Las Vegas portion of the show with Curt Menefee and Steve Farhood on location in Nebraska.

Quick return for Donaire?

New unified bantamweight champ Nonito Donaire took no punishment and barely worked up a sweat in pulverizing Fernando Montiel inside of two rounds last week at Mandalay Bay in Las Vegas, so he is hopeful to be back in the ring in short order, which his Top Rank manager, Cameron Dunkin, and HBO are discussing.

Dunkin told ESPN.com the hope is that Donaire could be back in the ring in May, although that seems unlikely based on HBO's schedule. Whenever Donaire returns, a potential opponent could be titleholder Anselmo Moreno of Panama in a unification bout, Dunkin said.

"That's what we're talking about," Dunkin said. "Bob [Arum] is saying, 'We can put this thing together and get him in the ring in May on HBO."

Top Rank would like to bring Donaire's next fight to the San Francisco Bay Area, where Donaire (26-1, 18 KOs), a native of the Philippines, grew up. That area is home to one of the largest Filipino communities in the United States.

"Nonito would love to get back in the ring quickly. We'd all love that after that performance," Dunkin said.

The knockout of Montiel was a star-making kind of performance for Donaire, who broke into the top five on the pound-for-pound list with the victory.

Dunkin said he planned to look at video of Moreno as well as have Robert Garcia, Donaire's trainer, look at it.

"I haven't seen Moreno yet," Dunkin said. "I will try to watch him and I will have Robert watch him and see what he thinks, but Arum is already saying this guy is perfect [for] the fight he wants to do. Hey, it's another belt that Nonito can win, but it's not just a belt. Moreno is a credible guy and it would be another appearance on HBO. So it would be a great opportunity."

Moreno (30-1-1, 10 KOs), a 25-year-old southpaw from Panama, has defended his belt seven times. He won his title by outpointing Wladimir Sidorenko in May 2008 and also won a split decision against Sidorenko in a rematch. Donaire blew Sidorenko out in four rounds in December.

• American fight fans will be able to watch live coverage of middleweight titleholder Dmitry Pirog's first defense on ESPN3.com, ESPN's streaming video site, Pirog co-promoter Artie Pelullo said. Pirog (17-0, 14 KOs) faces Argentina's Javier Francisco Maciel (18-1, 12 KOs) on March 26 in Ekaterinburg, Russia, his home country. "I think its very good for Dmitry to be on ESPN. It will give the fans in the United States another opportunity to see one of the best middleweights in the world," Pelullo said. "We hope for big things for him in the United States in the future." Pirog announced his arrival on the world stage when he scored an upset fifth-round knockout against highly touted American Daniel Jacobs on July 31 on the Juan Manuel Marquez-Juan Diaz II HBO PPV undercard.

• Joel "Love Child" Julio is returning to the welterweight division to face Antwone Smith on "Friday Night Fights" (ESPN2) at the 2,400-seat Amerihealth Pavilion, the smaller arena at the Prudential Center in Newark, N.J., on May 20, Main Events promoter Kathy Duva told ESPN.com. Julio (36-4, 31 KOs), 26, was stopped in the 11th round by Alfredo Angulo in an interim junior middleweight title bout on HBO in April 2010 and returned to outpoint Jamaal Davis in August. Three of Julio's losses have been at junior middleweight. "That's been the plan for some time," Duva said of Julio dropping down in weight. "He wants to go back to welterweight and that's what we all agreed he needs to do. Junior middleweight is just not the weight class he belongs in." Smith (20-2-1, 12 KOs), 24, was stopped in the ninth round by Lanardo Tyner in an upset in July and has won two bouts since. Lou DiBella, Smith's promoter, believes their styles will mesh for an exciting fight. "It's anybody's fight," DiBella said. "That's a great fight, great matchmaking. Styles make fights and it can't be a bad fight. That's a night everyone will be happy they have ESPN2."

• Denver junior welterweight Mike Alvarado (29-0, 21 KOs) was supposed to face Vernon Paris (24-0, 14 KOs) of Detroit on April 16 on Showtime in the opening bout of the card headlined by featherweight titlist Juan Manuel Lopez against Orlando Salido. However, the fight is off, Top Rank matchmaker Brad "Abdul" Goodman told ESPN.com. Goodman said Alvarado suffered a torn biceps during his tuneup fight against Dean Harrison on Feb. 19. Alvarado laid a beating on Harrison, forcing him to retire on his stool after the fourth round on the undercard of Nonito Donaire's second-round knockout of Fernando Montiel on Saturday. However, Alvarado suffered the minor tear during the fight and will be sidelined for a month or two. Top Rank is working on putting together a new fight to open the April 16 card in Puerto Rico.

• The rematch between junior flyweight titlist Luis Lazarte (48-9-2, 18 KOs) and former titlist Ulises Solis is set for April 30 in Buenos Aires, Argentina, Lazarte's home country, according to Sean Gibbons, matchmaker for Solis co-promoter Fernando Beltran. Lazarte's promoter, Osvaldo Rivera, won the recent purse bid for $300,000 ($225,000 for Lazarte and $75,000 for Solis) and this week set the date. Mexico's Solis traveled to the same venue to challenge Lazarte on Dec. 18 and came away with a disputed draw. Solis (32-2-3, 21 KOs) appeared to win the fight and the Lazarte committed numerous fouls for which he was not penalized, causing the IBF to order the rematch.

• Junior middleweight contender Vanes Martirosyan (28-0, 17 KOs) has not fought since outpointing Joe Greene on HBO at Yankee Stadium on the Miguel Cotto-Yuri Foreman undercard in June. He was mentioned for several potential fights, including one possibly against Cotto. Time and again, bouts fell apart. Now, he is scheduled once again to return to action. Martirosyan is slated to fight in Montreal on March 19 on the undercard of super middleweight titlist Lucian Bute's defense against Brian Magee. The main event will be televised on Showtime, although Martirosyan's fight, against an opponent to be determined, is not scheduled to be part of the broadcast. According to Carl Moretti of Top Rank, the company worked out a deal with Bute promoter InterBox to put Martirosyan on the card.

• Cruiserweight titlist Marco Huck (31-1, 23 KOs) of Germany will make his sixth defense against former titleholder Giacobbe Fragomeni (27-3-1, 11 Kos) of Italy on April 2 in Halle, Germany, and Huck is predicting a knockout. "There is a reason why I am the champion and not you," Huck said to Fragomeni at a recent news conference announcing the fight. "I am better and stronger and I will put you down. This is where I grew up, so I will have a lot of fans supporting me, and I will deliver them a spectacular night of boxing." Fragomeni took the prediction in stride, saying, "I have not seen Huck fight yet. I leave that to my coach. He will analyze him and come up with a plan on how to beat him." Huck had to get in the last word, adding, "I don't care whether you have watched me on tape or not. You will go down."

• British junior welterweight Frankie Gavin (9-0, 8 KOs), 25, one of boxing's best prospects, has his sights set on the British title and hopes to challenge Ashley Theophane, an American-based Brit who captured the belt by outpointing Lenny Daws last week in London in a mild upset. On the same night, Gavin stopped Michael Lomax in the seventh round. Gavin, a 2008 Olympian, hopes it leads to the fight with Theophane. "It doesn't really matter who holds that British title, I feel I am ready for anyone," Gavin said. "Congratulations to Theophane because he beat a good fighter in Daws to win that Lonsdale belt, but what would I have done to Daws? Theophane's now got something that I want, and I am going to be coming after him big time to get it. I've seen his fights and he's a class act. But I'll beat him hands down if he step up to the plate and faces me. Hopefully my promoter, Frank Warren, can get me a British title fight within the next few months." Said Warren, "Frankie's win on Saturday night showed he is ready for anyone in Britain. I'd make the fight with Theophane in a heart-beat. Frankie is a world class talent, not just a British-level talent. He'll win the British title this year, but it will be just the first of many belts he is going to get in his career."

• Saturday's heavyweight fight in Germany between Luan Krasniqi and American Johnathon Banks has been canceled. In the final days of training, Krasniqi came down with what was termed "a severe sinus infection." Said Krasniqi: "I am extremely disappointed and feel very sorry for my fans but a fight Saturday is simply not possible." Fortunately for Banks, he had not yet left for Germany when the fight was called off. "I was really looking forward to having this fight in Germany as the main event on RTL German television. I hope the fight will be rescheduled," Banks said. The whole card was called off.

• Former junior welterweight titlist Kendall Holt and former two-time lightweight beltholder Julio Diaz, both trying to remain relevant, will meet in a crossroads fight May 13 in a "Friday Night Fights" (ESPN2) main event at the Chumash resort in Santa Ynez, Calif. … The date and venue for junior featherweight titlist Steve Molitor's third fight with South Africa's Takalani Ndlovu is set. Molitor, who already owns two wins against Ndlovu, will face him in Johannesburg on March 26 after Ndlovu's promoter, Branco Sports, won the purse bid. … Planet Hollywood in Las Vegas will play host to a pay-per-view card March 11 ($24.99) headlined by a heavyweight fight between former title challenger Michael Grant (46-4, 34 KOs) and Tye Fields (44-2, 40 KOs) with former lightweight and junior lightweight champion Joel Casamayor (37-5-1, 22 KOs) facing former junior lightweight titlist Mike Anchondo (30-3, 19 KOs) in the co-feature. … To prepare for his middleweight championship defense against Sergei Dzinziruk on March 12 (HBO), Sergio Martinez is sparring with former junior middleweight titlist Daniel Santos (who lost his belt to Dzinziruk), junior middleweight titlist Austin Trout and junior welterweight contender Victor Cayo, according to adviser Sampson Lewkowicz.

Quotables

"I'm back because I want to be back and I'm ready. Other opponents were offered to me, but Maidana is a great opponent for me and who I want to fight." -- former three-division champion Erik Morales, at this week's kickoff news conference in Los Angeles announcing his April 9 HBO PPV headline fight against junior welterweight contender Marcos Maidana.

"He has the heart of a lion and I'm going to fire back with everything I've got when we engage. The fans can expect bombs to explode when Katsidis and I step in the ring. I believe this fight will be the fight of the night." -- lightweight contender Robert Guerrero, at this week's kickoff news conference promoting his fight against Michael Katsidis on the undercard of Golden Boy's April 9 HBO PPV card.